Which OSPF feature would be best to achieve this goal?

Refer to the exhibit.

OSPF is running throughout the network and RIP is being redistributed into OSPF in R2. You want
to minimize the propagation of LSAs into and out of Area 1.
Which OSPF feature would be best to achieve this goal?

A.
stub

B.
totally stubby

C.
NSSA

D.
totally NSSA

Explanation:
We need to redistribute RIP from R1 to Area 1 so Area 3 cannot be a stub or totally stubby area.
To minimize the propagation of LSAs into and out of Area 1 we should configure it as a totally
NSSA. Notice that a NSSA allows LSA Type 3 & 7 while a Totally NSSA only allows LSA Type 7
Note: Both Totally Stubby Area & Totally Stubby NSSA do not accept external AS routes or interarea routes (LSA Types 3, 4 and 5). They recognize only intra-area routes and the default route
0.0.0.0. The main difference between them is Totally Stubby NSSA accepts routes from other AS
while Totally Stubby Area does not.
Below summarizes the LSA Types allowed and not allowed in area types:
Area Type

Type 1 & 2 (within area)
Type 3 (from other areas)
Type 4
Type 5
Type 7
Standard & backbone
Yes
Yes
Yes
Yes
No
Stub
Yes
Yes
No
No
No
Totally stubby
Yes
No
No
No
No
NSSA
Yes
Yes
No
No
Yes
Totally (stubby) NSSA
Yes
No
No
No
Yes